Is it safe to buy a used BCD?

Are there any potential risks associated with purchasing a used BCD for diving? Should I be concerned about the condition of the equipment, or is it generally SAFE to buy used? Are there any specific checks I should make before making a purchase to ensure the BCD is in good working order? And if I do decide to buy a used BCD, are there any tips or best practices for maintaining and caring for it to ensure its longevity and safety?